Androgenetic alopecia (AGA) is a genetically based disorder of the scalp, which results in gradual and permanent miniaturization of the hair follicles on regions of the scalp ultimately resulting in baldness. This condition, while not life threatening, is psychologically highly devastating in affected people and can result in depression and poor quality of life.
Research has shown that the phenomenon is connected to the male hormone testosterone. Kaufman, K D, “Androgens and alopecia,” Mol. Cell. Endocrinol., 198(1-2), 89-95 (2002). Women and men with low levels of testosterone are less susceptible to AGA. Yet testosterone by itself is not sufficient to trigger the process. The process requires an additional step of chemical transformation in order to be effective. This additional process was shown to be the testosterone reduction to dihydrotestosterone (DHT), the ultimate baldness effector. Choi et al., “Biochemical roles of testosterone and epitestosterone to 5 alpha-reductase as indicators of male-pattern baldness,” J. Invest. Dermatol., 116(1), 57-61 (2001).
The conversion occurs in the body by means of the enzyme 5α-reductase, which is abundant in the skin and follicles of susceptible individuals. It is this same hormone that stimulates sebaceous glands, located in hair follicles, to produce sebum which is then secreted onto the skin. An excessive sebum production is known as seborrhoea and is often associated with AGA. Mercurio et al., “Androgen physiology and the cutaneous pilosebaceous unit,” J. Gend. Specif. Med., 3(4), 59-64 (2000). Seborrhoea exacerbates the effects of balding because it causes stickiness of hair and favours the production of dandruff.
Dandruff itself (Pityriasis capitis) is another relevant problem for balding individuals and a potential source of stress and social embarrassment. It is due to an excessive turnover of scalp skin which in turn results in copious shedding of whitish flakes. The cause of dandruff has been identified in the fungus Malassezia globosa which metabolises scalp triglycerides (sebum) into oleic acid which is an irritant and provokes the turnover increase. Therefore, the three problems mentioned are all connected and tend to afflict overlapping groups of individuals.
Many compounds to date have been shown to inhibit DHT formation from testosterone, such as finasteride, dutasteride, zinc, and azelaic acid. See, Stamatiadis, et al. “Inhibition of 5 alpha-reductase activity in human skin by zinc and azelaic acid,” Br. J. Dermatol. 119(5), 627-32 (1988); Olszewska et al., “Effective treatment of female androgenic alopecia with dutasteride,” J. Drugs Dermatol., 4(5), 637-40 (2005); and Leyden et al., “Finasteride in the treatment of men with frontal male pattern hair loss,” J. Am. Acad. Dermatol., 40(6 Pt 1), 930-7 (1999). Of these, finasteride has been licensed for commercial use for the purpose of preventing AGA.
Many other compounds have been shown to stimulate hair growth by yet unclear mechanisms which may be connected to increased blood supply to the follicle and stimulated cell proliferation. These include minoxidil and tretinoin. See, Karam P., “Topical minoxidil therapy for androgenic alopecia in the Middle East. The Middle-Eastern Topical Minoxidil Study Group,” Int. J. Dermatol., 32(10), 763-6 (1993); and Bazzano et al., “Topical tretinoin for hair growth promotion,” J. Am. Acad. Dermatol., 15(4 Pt 2), 880-883 and 890-893 (1986). Minoxidil has been licensed for commercial use for the treatment of AGA.
The saw palmetto extract is a common herbal supplement taken orally and known to be beneficial in enlarged prostate patients. Medical research has shown that it is a good inhibitor of 5α-reductase, the enzyme responsible for generating DHT, the harmful form of testosterone. See, Habib, F. K., et al. “Serenoa repens (Permixon) inhibits the 5 alpha-reductase activity of human prostate cancer cell lines without interfering with PSA expression”, Int. J. Cancer 114 (2), 190-4 (2005). It is widely available, taken systemically, and has a good safety record. The only common remedy for sebum overproduction is detergency. To this date, there are no topical formulas with a proven capacity to reduce sebum production, therefore, the only option is sebum removal once produced. There are many detergents available, but they all come with the drawback that a rinse is required to flush them and so access to water and hair drying equipment is necessary. For dandruff prevention fighting the responsible fungus will dramatically alleviate the condition. Many antifungal compounds are used cosmetically as additives to shampoos, including zinc pyrithione, tar, selenium sulfide, and ketoconazole. These compounds all have a long usage history which has proven they are effective and safe to use.
The prior art relates to treatment of the hair strands themselves (such as thickening) and not skin penetration. Moreover, there is no intent to deliver active ingredients to hair follicles or to treat sebum. The present invention is directed to addressing the need for compositions that remove excess sebum and dandruff while also stimulating hair growth.